1. Field of the Invention
The present invention relates to an endodontic filing tool which can be mounted with a slight play in a dental tool holder while being secured against rotation as well as against axial movement.
2. Description of the Related Art
A tool and tool holder of the above-described type are known from Austrian patent 388,283. The content of this Austrian patent is incorporated herein by reference. In order to hold the tool in the tool holder, the Austrian patent 388,283 provides that the rearward end of the shaft of the tool has at least one spherically-shaped recess and at least one chucking ball is provided in the tool holder, wherein the chucking ball is pressed radially inwardly into the spherically-shaped recess by means of a spring. The spring does not have to act directly against the ball; rather, particularly when several balls are provided, a force-transmitting structural component may be provided.
The tool holding machanism described above operates as required, however, the mechanism is difficult to manufacture because the spherically-shaped recesses can only be manufactured by means of high precison tools and the assembly of the tool requires a careful and sensitive treatment in order to engage the ball or balls in the recess or recesses.